Tiny solar cells fix themselves

Sunday, 05 September 2010 21:24

Researchers have demonstrated tiny solar cells just billionths of a metre across that can repair themselves, extending their useful lifetime. The cells make use of proteins from the machinery of plants, turning sunlight into electric charges that can do work. The cells simply assemble themselves from a mixture of the proteins, minute tubes of carbon and other materials.

The self-repairing mechanism, reported in Nature Chemistry, could lead to much longer-lasting solar cells. The design and improvement of solar cells is one of the most vibrant areas of science, in part because sunlight is far and away the planet's most abundant renewable energy source.

More than that, nature has already proven that sunlight can be captured and turned into other forms of energy not only with extraordinary efficiency but also with a self-repair mechanism that counteracts the ravages of sunlight.

"Sunlight, when it hits oxygen, is very damaging," explained Michael Strano, the Massachusetts Institute of Technology chemical engineer who led the research. "It's the reason why we age, and the reason why when we leave paper or plastic out in the sun, it fades."

The destructive mixture of sunlight and oxygen, Professor Strano told BBC News, means that many of the best solar cells in the laboratory might not survive well when put into use.

"There's a kind of a horse race among scientists around the world to make the highest efficiency cell, but very few people are asking what happens with that cell when you plug it in for a few hours or for a week or for months," he said.